He went to Locust Valley High School before playing college football at C. W. Post.
While in high school, he was an all-star selection as an outfielder in baseball, a center in basketball, and a two-way player in football.
By his sophomore year at C. W. Post he was already considered to be one of the best defensive players, with 12 sacks, three blocked punts, three passes defended, and 64 tackles by mid-November.
An article by Newsday said that a television crew from NBC was poised by Mohring during the entire day one of the draft, but he was not selected.
[7] In a game against the Houston Oilers, he recovered a fumble on the opening kickoff to help his team win, 17–14.